9. Draw lines dividing it into square inches. How many square inches are there in one long row? How many rows? 10. How many square inches in all? (3 × 5) sq. in. are 15 sq. in. 11. On the schoolroom floor draw a rectangle 5 ft. long and 3 ft. wide. Draw lines dividing it into square feet? How many are there? (3 × 5) sq. ft. are 15 sq. ft. The number of square inches, square feet, square yards etc. that a rectangle or other figure contains is its area. 12. What is the area of a rectangle 9 in. by 7 in.? 13. What is the area of a rectangle 10 ft. long and 8 ft. wide? Of a lawn that is 5 rd. long and 4 rd. wide? Dia TO THE TEACHER. In the grades below the fifth, much work has been done upon the fundamental idea of computing area. grams have been made showing the number of square units to be equal to the product of the numbers of linear units in the length and breadth. It would be well for the teacher to present the idea again here, in the same manner, although children should be able, by this time, to use the process understandingly as presented, just as they multiply by a number of three figures without analyzing the process every time. The area of a rectangle is found by multiplying its length by its breadth, both expressed in the same kind of units. Written 1. How many acres are there in a rectangular field 40 rd. long and 28 rd. wide? 28 (rd.) 40 (rd.) 160)1120 (sq. rd.)(7 A. Ans. 112 Such problems may be shortened by cancellation, thus: 2. How many square yards are there in a piece of pavement 300 feet long and 38 feet wide? The number of square feet is 38 × 300. The number of square yards is 38 × 300 ÷ 9. NOTE. Areas are seldom expressed in two denominations, but rather in an integer or a mixed number of one denomination. For instance, the area in problem 2 is 12663 sq. yd. rather than 1266 sq. yd. 6 sq. ft. 3. How many square feet of surface are there in a table top that is 2 ft. wide and 3 ft. 4 in. long? 4. A square mile of land is called a section. How many acres are there in a quarter section? In of a section? 5. a. A school garden 4 rd. by 8 rd. contains how many square feet of land? (First change the dimensions to feet.) b. In this garden, 612 sq. ft. were rose beds, and other permanent uses. feet were left for other uses? given up to paths, How many square c. How many square yards were left? 6. Mrs. Brown's guest room is 20 ft. 6 in. long and 16 ft. wide. a. How many square feet of hardwood floor does it require? b. How much will the floor cost at 18¢ a square foot? 7. This is a hall floor. How many square feet of floor does it contain? 8. The floor of Howard's Reduce 6" and 2" to fractions of a foot. 18' 6" room has an area of 168 sq. ft. It is 12 ft. wide. How long is it? 168 is a product; 12 is one of its factors. How will you find the other factor? 9. A department store in our city has 28,800 sq. ft. of floor space on each floor. It is 120 ft. wide. How long is it? 96' 96' 10. This represents the floor of our gymnasium. Area 6912 sq. ft. Find its width. 11. A 10-acre field is 50 rd. long. How wide is it? (Since there is no denomination in linear measure that corresponds to acres, first reduce 10 acres to square rods.) 12. Our manual training shop is 14 yd. long and 11 yd. wide. The eighth-grade boys put a concrete floor in the basement. How much would it have cost at 10¢ a Oral Review and Practice 1. Edward earned $3 in one week and $6 the next. How much money was left after he had used & of it? 2. When 16 gallons of molasses cost $16, what is the cost per quart? 3. Mr. McCrea bought an acre of land and cut it into 5 lots of equal size. How many square rods were there in each? 4. Name two numbers that are prime to each other. 5. Change to 9ths. 6. Change to a fraction whose terms are prime to each other. 7. What is the smallest number that will exactly contain 8 and 12? 8. 16 is the sum of 10% and what other number? 9. Esther spent 5 cents for carfare, 4 cents for pencils, 8 cents for paper, 10 cents for ribbon, and 15 cents for lunch. She had 9 cents left. How much money had she at first? 10. A man in repairing his house paid $65 for lumber, $8 for paint, $1 for nails, and $30 for labor. What was the cost of his repairs? 11. How many rods are there in 2 mi.? 13. Name 3 factors of 30. 14. Name all the numbers that are factors of 24. 15. If a bushel of oats weighs 32 lb., what is the weight of 31 pk.? 16. Alma made a tray cloth of a yard long and § of a 흉 yard wide. What part of a square yard will it cover? 17. Clarence made a jelly-squeezer for his mother. He found a board 2 ft. long and cut off 3g". How long was the piece remaining? It was 9" wide. He sawed it lengthwise, making two equal pieces, then planed them down so that each piece was 41" wide. How much of the width of each piece the other, bent a piece of tin over the remaining ends for a hinge, so that it extended back 34" on the outside of each piece, and nailed it to both pieces. The boards were " thick. How long was the piece of tin? 19. Subtract the fractions as given in question 18. 20. of 1 = ? § of } = ? } of } = ? 23. Larry paid 10¢ for 4 apples. What would a dozen cost at the same rate? (12 = how many times 4?) 24. When oranges are 40¢ a dozen, what should be paid for three? (Three = what part of a dozen?) 25. When tomatoes are $1.50 a dozen cans, what should I pay for 6 cans? 26. Mary bought 18 inches of cloth from a piece that sold at $1 a yard. What did she pay? |